Gene therapies, especially chimeric antigen receptor (CAR) T-cell therapies, experienced significant growth in 2017. The CAR T-cell therapies are among the most clinically important of the adoptive cell transfer therapies. In August, the FDA approved tisagenlecleucel for patients aged < 26 years with acute or relapsed lymphoblastic leukemia (ALL). In October, the FDA approved axicabtagene ciloleucel for treatment of adult patients nonresponsive to, or relapsed from treatment of, certain types of large B-cell lymphoma. And in November, the FDA granted breakthrough therapy designation to Celgene and Bluebird Bio for the bb2121 anti-B-cell maturation antigen (BCMA) CAR T-cell therapy for relapsed and refractory multiple myeloma (MM).